Distant hybridization is an important breeding technique for creating new strains with superior traits by integrating two different genomes. Successful hybridization of Megalobrama amblycephala (Blunt snout bream, BSB, 2n = 48) and Culter alburnus (Topmouth culter, TC, 2n = 48) was achieved to establish hybrid lineages (BT and TB), which provide valuable materials for exploring the mechanisms of distant hybridization fertility. In this study, the gonadal tissue transcriptomes of BSB, TC, BT-F1, and TB-F1 were sequenced using Illumina high-throughput sequencing technology to analyze the reproductive characteristics of BT and TB. Differential gene expression analysis showed that the differentially expressed genes in BT vs BSB and BT vs TC were mainly enriched in signaling pathways not directly associated with meiosis. While, the differentially expressed genes of TB vs BSB and TB vs TC were mainly enriched in pathways related to meiosis, and most of them were down-regulated, indicating that meiosis is suppressed in TB. Under-dominance (UD) genes were enriched in pathways related to meiosis and DNA repair in TB. Over-dominance (OD) genes were enriched in MAPK signaling pathway, expression level dominance-BSB (ELD-B) genes were enriched in pathways related to steroid hormone synthesis and expression level dominance-TC (ELD-T) genes were not significantly enriched in any pathway in both BT and TB. These results suggest that meiotic progression may not be affected in BT, whereas it is clearly inhibited in TB. Offspring of M. amblycephala maternal parent may have better genomic compatibility and fertility. Our study provides important information on the molecular mechanisms of breaking reproductive isolation in distantly hybridized fertile lineages.

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团头鲂与白鲌杂交互杂谱系繁殖特性的比较转录组分析

远缘杂交是通过整合两个不同基因组来创造具有优良性状的新菌株的重要育种技术。团头鲂（Blunt snout bream，BSB，2n = 48）与鲳鱼（Topmouth culter，TC，2n = 48）的成功杂交，建立了杂交谱系（BT和TB），为探索团头鲂（Blunt snout bream，BSB，2n = 48）和鲳鱼（Topmouth culter，TC，2n = 48）的杂交谱系（BT和TB）提供了宝贵的材料。远缘杂交育性。本研究利用Illumina高通量测序技术对BSB、TC、BT-F1和TB-F1的性腺组织转录组进行测序，分析BT和TB的生殖特征。差异基因表达分析表明，BT vs BSB和BT vs TC中的差异表达基因主要富集于与减数分裂不直接相关的信号通路。而TB vs BSB和TB vs TC的差异表达基因主要富集于减数分裂相关通路，且大部分表达下调，表明TB减数分裂受到抑制。欠显性 (UD) 基因在结核病减数分裂和 DNA 修复相关通路中富集。过度优势（OD）基因在MAPK信号通路中富集，表达水平优势-BSB（ELD-B）基因在类固醇激素合成相关通路中富集，表达水平优势-TC（ELD-T）基因没有显着富集BT 和 TB 的任何途径。这些结果表明减数分裂进展在 BT 中可能不受影响，而在 TB 中明显受到抑制。团头藻母本的后代可能具有更好的基因组相容性和生育能力。我们的研究提供了有关打破远缘杂交可育谱系生殖隔离的分子机制的重要信息。